Catalytic and adsorbent gel



Patented Dec. 25,

UNITED STATES PATENT oFFrcs.

WALTER A. PATRICK, O1 BALTIMORE, MARYLAND, ASSIGNOR TO THE SILICA GEL CORPORATION, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

CATALYTIC AND ADSORBENT GEL:

No Drawing. Original application flied February 28, 1920, Serial No. 362,138. Divided and this application filed March 15, 1926.

The present invention, which is adivision of my application No. 362,138 filed February 22}, 1920,.relates to adsorbent gels having chemlcally active or catalytic agents associated therewith, and more particularly to such gels having a copper bearing material associated therewith. i

In my Patent No. 1,297,724: I have disclosed the method of making a hard, highl porous silica gel, stable up to 700 C. an havmg ultra-microscopic pores.

It is the principal object of the present 1nvention to produce gels similar in physical structure to the gel described in the above patent, but which possess special properties due to the incorporation of a copper bearing material, for example, copper oxide.

The present invention comprehends a hard, stable, porous material having ultra-microscopic pores substantially the same as the silica gel mentioned above, and havmg associated therewith a copper bearing material.

From a chemical standpoint, it is very desirable to have certain substances in a physical structure similar to that of a porous gel such as the silica gel described in said patent. Silica is an inert substance chemically, and for this reason is admirably suited for adsorbing and removing gases and vapors, provided, of course, that it has the proper porous structure. On the other hand, other substances, such as copper and copper ox1de, are known to possess desirable chemical and catalytic properties. If this metal or metallic oxide can be obtained with a structure similar to that of the gel described in the patent, the above properties are enhanced and made more active, because of the large surface presented.

According to the present invention it is possible to obtain a gel of the structure disclosed in the patent having a copper bearing material, such as copper or copper oxide, incorporated therew1th.

In the preparation of silica gel as described in the patent, use is made of the reaction between a soluble silicate and an acid to produce colloidal silicic acid. It is found necessary to allow the silicic acid to, set to a hydrogel in a medium of certain definite acid concentration, in order to insure a gel of the proper structure. The concentration of the acid-in the mixtureis from about three tenths to nine tenth gram ions of hydrogen per litre, the preferred concentration being about Serial No. 94,959.

five tenths gram ions of hydro en per litre.

If a mixture of copper ch oride, water glass and hydrochloric acid be prepared of such a nature that the whole Will set to a hydrogel, itis found that it is possible to entirely free the mixture of chlorides b washing withoutloss of much copper. The loss *of copper in the washin depends upon the amount of acid used in the original mixture.

If improper proportions are taken, a precipitate will result and the product of the present invention not be obtained. On the other hand, if the proper proportions and quantities are taken, the mixture gradually hardens into a hydrogel. The hydrogel by washing and drying is converted into the highly porons gel of the present invention.

The precipitate mentioned above, after being washed and dried, may be the same chemically as the gel, but it does not have the same porous structure. The gel has much finer pores than the dried precipitate, and consequently the internal surface of the gel is many times as extensive as the internal surface of the'dried precipitate. It is because of this extensive surface that the gel of the present invention is so active catalytically.

In preparing the gels, the liquid after mixing should have an acid concentration of three tenths to nine tenths gram ions of hydrogen per litre. The product obtained after Washing and drying-is a hard glassy material having a porous structure substantially From the foregoing, it is apparentthat according to the present invention it is possible to obtain hard, adsorbent gels including copper or copper oxide, this mixture being secured from a copper salt, a silicate and acid, the proportions and concentrations being such as to give an acid concentration of three tenths to nine tenths gram ions of hydrogen per litre, in the liquid obtained by mixing solutions of the ingredients.

The term silica gel as used in the specification and claims, designates a hard, porous material having a porous structure similar 2. A hard stable n0n-precipitated silica 15 to that of the silica gel obtained by the process described in Patent No. 1,297,724.

The term copper bearing material as used in the specification and claims is intended to designate the metal copper by itself as well as compounds thereof.

Having thus described the invention, what is claimed as new and desired to be secured 1 Letters Patent is:

1. A hard stable-material having a porous structure substantially the same as silica gel and consisting of a colloidal oxide and copper oxide.

gel having ultra-microscopic pores and havmg copper oxide associated therewith.

3. A hard stable material having a porous structure substantially the same as silica gel and consisting of a colloidal oxide and a copper bearing material.

4. A hard stable non-precipitated silica gel having ultra-microscopic pores and having a copper bearing material associated therewith.

In testimony whereof I hereunto ailix my signature.

WALTER A. PATRICK. 

